The crumpled baby stroller was just the latest symbol of a persistent fear for city residents: the danger of crossing a street.

A 1-year-old boy and a 4-year-old girl were killed Monday afternoon after a crash near Ninth Street and Fifth Avenue in Park Slope, Brooklyn. A car, which appears to have run through a red light, dragged the stroller down the street, among other mayhem. Three women, including the driver of the car, were taken to hospitals. Initial reports said the driver told police she had a medical condition.

All pedestrian traffic deaths are tragic and infuriating, but the deaths of children pack a particular gut punch. It was in the aftermath of the death of a 9-year-old in 2014 that Mayor Bill de Blasio launched his Vision Zero initiative, vowing to end traffic deaths.

Getting to zero has proved difficult, but the city has seen encouraging decreases in traffic fatalities during de Blasio’s first term. Pedestrian deaths overall have dropped by 45 percent since 2013, with 101 deaths last year, even as cyclist deaths ticked up slightly. A single pedestrian schoolchild died in traffic in 2017. In 2004, 17 children were killed, according to city data.

As part of the effort, de Blasio’s smart Vision Zero initiatives have included a lower speed limit and safety infrastructure like medians and protected bike lanes. Monday’s tragic deaths make clear that more needs to be done.

Transportation advocates were quick to call for safety measures near the intersection, where a pedestrian was killed in 2016. The city Department of Transportation on Monday promised to consider a protected bike lane on Ninth Street. Similar protections would make a difference even if they can’t prevent every accident.

More details about what happened in Park Slope will better inform what must be done next to safeguard pedestrians. Parents are likely holding a little tighter to their kids’ hands this week.